Photographic processes and compositions useful therein



PHOTOGRAPHIC PROCESSES AND COMPOSI- TIONS USEFUL THEREIN No Drawing.Application November 23, 1954 Serial No. 470,802

4 Claims. (Cl. 96-29) Lexington, Mass., assignors to Cambridge, Mass., acorporation The present invention relates to photography and, moreparticularly, to diffusion transfer-reversal processes and compositionsuseful therein.

-In a typical diffusion transfer-reversal process, an aqueous solutionof a silver halide developer and a silver halide solvent is applied to asilver halide stratum and a silver-receptive stratum which are insuperposed relation. The developer and solvent cooperate to reduceexposed silver halide to silver, to react with unreduced silver halideto form a Water-soluble, complex silver salt, and to transfer the saltto the silver-receptive stratum where it is reduced to silver.

Developers and solvents, which in the past have been found to cooperatesatisfactorily in diffusion transferreversal processes, have sufferedvarious shortcomings. For example, certain developers, e. g.,hydroquinone, if unexhausted, react with atmospheric oxygen to form acolored product which stains the highlights of the image and, ifexhausted, oxidize silver to cause the image to fade. Also, certaincomplexing agents, e. g., ammonia, are often too weak to be fullyeffective in the production of transfer images; others, e. g., sodiumthiosulfate, leave on the transfer image a harmful sulfur residue; andstill others, e. g., sodium cyanide, are often impractical because oftheir dangerous toxicity.

The present invention contemplates a novel solution of the foregoingtype which contains effective components and leaves a harmless residue.Essentially, this solution includes a cyclic imide and a hydroxylamine.Preferably, it includes also a nitrogenous base, e. g., an amine, otherthan a hydroxylamine. Of these components, it is believed that thecyclic imide and the hydroxylamine and/or other nitrogenous basecooperate to perform a complexing function, and the hydroxylamine itselfperforms a developing function. It has been discovered that cyclicimides and nitrogenous bases which are not effective as complexingagents independently are very effective to gether. The coaction of thesecomplexing agents is the subject of copending patent application SerialNo. 378,684, filed September 4, 1953, in the name of Edwin H. Land etal. It has been discovered also that hydroxylamines, ordinarily weakdevelopers, are effective in diffusion transfer-reversal processes and,particularly, in diffusion transfer-reversal processes in which silvercomplexing is accomplished in the foregoing way. The striking coactionof cyclic imides and hydroxylamines is fortunate because: whenexhausted, they do not react with silver to deteriorate the image; theycan leave no sulfur residue since they are sulfur free; they may bereadily handled since they are relatively nontoxic; and they do notstain the image since their reaction products are pale or colorless.

Accordingly, objects of the present invention are: to provide, as anovel composition of matter, an alkaline aqueous solution comprising atleast one member of the class consisting of the cyclic imides and atleast one member of the class consisting of the nitrogenous bases, atleast one member of the former class and at least one United StatesPatent with respect to each of Although the foregoing formula is in ketoform,

class, together, being operative to form water-soluble, complex silversalts, at least one member of the latter class being a hydroxylamineoperative as a silver-reducing agent; and to provide diffusiontransfer-reversal processes employing such a composition. 4

Other objects of the invention will in part be obvious and will in partappear hereinafter.

The invention accordingly comprises the several steps and the relationand order of one or more of such steps the others, and the compositionpossessing the features, properties and the relation of elements whichare exemplified in the following detailed disclosure, and the scope ofthe application of which will be indicated in the claims.

For a fuller understanding of the nature and objects of the invention,reference should be had to the following detailed description.

Preferred cyclic imides to be employed, in accordance with the presentinvention, are characterized by the following general formula:

member of the latter (1) atoms of a series completing a cyclic imidenucleus consisting of from 5 to 6 atoms of which from 1 to 3 arenitrogen and the remainder are carbon, and (2) components branching fromthe atoms of the series, these components being selected from the classconsisting of hydrogen atoms, amino radicals, aliphatic radicalscontaining from 1 to 4 carbon atoms, halogen atoms, keto oxygen atomsand aromatic radicals, at most one of these components being one of thehalogen atoms, keto oxygen atoms and aromatic radicals.

it is intended to encompass the enolic modifications of compounds withinits scope.

Typical preferred cyclic imides, corresponding to the foregoing generalformula, are triazines, barbiturates, uracils, urazoles, hydantoins,glutarimides, glutaconimides, succinimides and maleimides, of which thefollowing are examples:

wherein Z represents Barbituric acid fi me'thyl uracil -caxboxi uracil HI c l-ethyl-G-methyl uracil 5-carboxymethyl--. amino uracil 4,5 dimethyluracil Glutarimide 'H 'Glqtaconimida L'Cltrazinic. acid HN HI lHydroxylamine (2) N-methylhydroxylamine (3) N-ethyl hydroxylamine (4)N-propyl hydroxylamine 5 N-isopropyl hydroxylamine (6) N,N-diethylhydroxylamine (7) N,N-dimethylhydroxylamine 8) N-methyl-N-propylhydroxylamine 9) N-methyl-N-isopropyl hydroxylamine l 0)N-ethyl-N-propyl hydroxylamine (1 1) N,N-diisopropyl hydroxylamine l2)N,N-di-n-propyl hydroxylamine 13) N-ethyl-N-methylbutyl hydroxylamine(l4) N-methyl-N-isobutyl hydroxylamine 15 N-n-propyl-N-n-butylhydroxylamine 16) N-hydroxy-pyrrolidine (17) N-hydroxy-piperidine l 8)N-hydroxymorpholine (19) N-benzyl hydroxylamine H0 CHzCfi:N-ethyl-N-hydroxyethy1 hydroxylamlne N OH O IHB 0 2 N-benzyl-N-methylhydroxylamlno H 0 C H: C1\I:

NOH HO O C CH:C H: N-hydroxyethyl-N-carboxyethyl hydroxylamlne NHOHa-Hydroxylamine-fi-phenyl propionic acid N-phenyl hydroxylamlneHOOCQNHOH N-p-carboxy phenyl hydroxylamine CHzOQ-NHOH N p-methoxy phenylhydroxylamiue $11 (in N.Nmethy1ene bis (N-phenyl hydroxylamine) (28)50:11

NHOH

m-Hydroxylamino-benzene sultonic acid As indicated above, the mosteffective solutions of the herein contemplated type comprise, inaddition to a cyclic imide and a hydroxyl amine, a nitrogenous baseother than a hydroxylamine. Where the hydroxylamine is aliphatic, it mayperform a developing function as well as a complexing function incooperation with the cyclic imide. In any case, the addition of anitrogenous base, which performs a complexing function exclusively, herehas been found desirable. Where the hydroxylamine is aromatic, it is arelatively strong developing agent and does not cooperate effectivelywith the cyclic imide to form a stable silver complex. In this case, theaddition of a nitrogenous base which cooperates with the cyclic imide inthe performance of a complexiug function ordinarily is required. Such anadditional nitrogenous base preferably is selected from the classconsisting of ammonia, amines, hydrazine and aliphatic hydrazines whichare soluble in aqueous alkali. As examples of nitrogenous bases selectedfrom this class, mention may be made of:

(1) Ammonia (2) Sec. amylarnine (3) Ethylamine (4) n-Butylamine (5)Allylamine (6) Diethylamine (7) Dipropylamine (8) Trimethylamine (9)Triethanol amine 10) NH CH CH NHCH CH NH Dlethylene triamlne NH (CH CHNH) CH CH NH Tricthylene tetramlne CHzCHCHzNH:

NHCHaCHrOH N-hydroxyethyl propylene diamine NH CH CH CH NH Trimethylenediamine (14) NH CH CH NH Ethylene diamlne NHs-CHsCIi:

NH H0 CHrC: Amlnoethyl ethanol amine HOCH2CHzNHCHzCHgNHCHgCHgNHzHydroxyethyl diethylene trlamlne NH CH CH NH) gcHgcHgNHg Tetraethylenepentamine l 8) Guanidine hydrochloride (l9) Piperidine (20) PyrrolidineCHI e-H 7 [-C H NH1 Polyethylene imine p-Aminophenol NH on-211012,4-diaminophenol dihydrochlorlde Meta-amino-benzoie acid (26) Hydrazine(27) Methyl hydrazine Unsymmetrical dimethyl hydrazine The alkalinity ofthe solution for good results must be high, ranging from a pH of 11 to ahydroxyl ion concentration of N. As examples of bases which are capableof imparting such an alkalinity to the composition, mention may be madeof alkali-metal hydroxides such as sodium and potassium hydroxide andamines such as diethylamine and allylamine. Such a nitrogenous base asdiethylamine can perform, at once, both this function and a complexingfunction.

In one transfer process of the contemplated type, the solution is spreadin a uniformly thin layer between the superposed surfaces of aphotoexposed gelatino silver halide stratum and a silver-receptivestratum, for example by advancing the strata between a pair ofpressureapplying rollers. The strata are maintained in superposedrelation for a predetermined period, preferably of the order of 40 to120 seconds in duration, during which exposed silver halide is reducedto silver and unreduced silver halide forms a water-soluble, complexsalt which diffuses through the layer of solution to the image-receptivestratum, there to be reduced to silver and to form a visible print. Atthe end of this period, the silver halide stratum is stripped from theimage-receptive stratum. Materials useful in such a transfer process aredescribed in U. S. Patent No. 2,543,181, issued in the name of Edwin H.Land on February 27, 1951.

The silver-receptive stratum, preferably,- includes certain materialsthe presence of which, during the transfer process, has a desirableeffect on the amount and character of silver precipitated on thesilver-receptive stratum. Materials of this type are specificallydescribed in copending U. S. patent applications Serial No. 727,385,filed by Edwin H. Land on February 8, 1947 (now Patent No. 2,698,245)and Serial No. 449,995, filed by Edwin H. Land on August 16, 1954 (nowPatent No. 2,698,237).

A composition employed in the foregoing manner preferably is relativelyviscous, of the order of 100 to 200,000 centipoises at a temperature of20 C., so as to be easily controlled when spread. If desired, theviscosity of the composition can be increased byincluding within it asuitable thickening agent, such, for example, as a watersoluble,synthetic polymer, an insoluble, emulsifiable oil, a starch, or a gum.It is possible for such a nitrogenous base as polyethylene imine toperform, at once, both a thickening function and acomplexing function.

Stripping of the silver halide stratum from the silverreceptive stratumseparates the layer of processing solution from the silver-receptivestratum or permits the layer of processing solution to remain in contactwith the silverreceptive stratum in order to provide it with aprotective coating. Techniques which enable such stripping to beaccomplished as desired are taught in U. S. Patent No. 2,647,056, issuedto Edwin H. Land on July 28, 1953. In general, the reaction productresidue of the solution and silver halide, which is present on thesilver image either as a trace remaining after the processing solutionlayer has been separated from the silver or which remains as aprotective coating on the silver image, as indicated above, is colorlessor pale, so as not to appreciably affect the appearance of the image andhas little tendency to react with reduced silver to deteriorate theimage. However, any existing tendency of this residue to harm the imagemay be minimized by so formulating the solution that as many of itscomponents as possible are volatile. Thus, in a preferred form, theprocessing solution comprises, in addition to a cyclic imide which isnot volatile, a volatile nitrogenous base, e. g., ammonia or a lowmolecular weight amine, as a complexing agent, and a volatilehydroxylamine, e. g., hydroxylamine or a low molecular weighthydroxylamine, as a developing agent. Here, the tendency of theprocessing solution residue to continue to form silver complexes isminimized by volatilization of the nitrogenous base and the tendency ofthe processing solution residue to harm the image and to form a coloredproduct is minimized by volatilization of the hydroxylamine.

The following nonlimiting examples further illustrate the presentinvention:

EXAMPLE I Barbituric acid 9:2 Diethyl hydroxylamine 3.7 Aminoethylethanol amine 1.7

The excellent image which was formed in the silverreceptive stratum wasof blue-black tone and moderate contrast and had a maximum density of1.7 and a minimum density of 0.02.

Excellent results also were obtained with formulations similar to theforegoing except that: the barbituric acid was replaced by an equalquantity of sodium barbital, cyanuric acid, urazole, uracil, hydantoin,carboxymethyl barbituric acid, or 4-carboxy-uracil; the diethylhydroxylamine was replaced by an equal quantity of dimethylhydroxylamine or propyl hydroxylamine; the aminoethyl ethanol amine wasreplaced by an equal quantity of triethylene tetramine, guanidinehydrochloride or allylamine, or 3.4 parts of piperidine, pyrrolidine orhydroxyethyl propylene diamine. The characteristics of an image formedin the fore going way may be varied as desired by varying the relativeproportions of the components, of a formulation of the foregoing type.Thus:

EXAMPLE II Parts by weight Water 73.6

Sodium carboxymethyl cellulose (high viscosity) 2.6

Sodium hydroxide 9.2 Urazole 10.0 Diethyl hydroxylamine 6.0

Aminoethyl ethanol amine 2.0

The resulting image was of blue-black tone and moderate contrast and hada maximum density of .98 and a minimum density of .09.

7 EXAMPLE III The following formulation produced a less contrastyEXAMPLE IV The following formulation produced a light image of lowcontrast having a maximum density of .86 and a minimum density of .14:

Parts by weight Water D 73.6 Sodium carboxymethyl cellulose (highviscosity) 2.6 Sodium hydroxide 9.2 Urazole 3.0 Diethyl hydroxylamine6.0 Aminoethyl ethanol amine 2.0

EXAMPLE V The following formulation produced a contrasty image having amaximum density of 1.86 and a minimum density of .82:

Parts by weight Water 73.6 Sodium carboxymethyl cellulose (highviscosity) 2.6 Sodium hydroxide 9.2 Urazole 1.0 Diethyl hydroxylamine6.0

As indicated above, the proportions of the various compouents may bevaried within wide limits. However, where the processing period isshort, for example, ranging from 40 to 120 seconds (in accordance withthe now conventional duration of diffusion transfer-reversal processingperiods), practical results are achieved where, in concentrations bytotal weight of the solution, the cyclic imide ranges from 1 to 15%, thehydroxylamine ranges from 1 to 15% and the additional nitrogenous baseranges from to 15%. In one minute, the following formulations producedimages which, though distinct, were pale, indicating that ingredients inproportions outside these ranges would produce images of generallydecreasing worth.

Table I Components of the solution Percentage ot'Total Weightproportions of which are varied in formulations A B,C,D,E,F,G,Handi A B0 D E F o H r Barblturlc acid 1 15 1 15 1 15 1 15 Dlethylhydroxylamine.1 1 15 1 15 1 15 6 vminoethyl ethanolamin 1 1 1 0 15 1 15 15 0 aterSodium carboxymethyl cel- To make solution having pH of 12 and lulose.viscosity of 100,000 centipolses Sodium hydroxide In preparing theforegoing compositions, the sodium carboxymethyl cellulose and thesodium hydroxide first were dissolved in water at room temperature.Next, the cyclic imide was added to the solution and the two phases weremixed until the cyclic imide was completely dissolved. Simultaneously,the nitrogenous base or bases were added to the solution with suflicientmixing only to insure their dissolution, care being taken to preventoxidation and/or volatilization of the nitrogenous base or bases.

The present invention thus provides novel difiusion transfer-reversaltechniques employing silver halide developing and dissolving componentswhich are as efiicient as corresponding conventional components and yetwhich leave on the image which they form a harmless residue.

Since certain changes may be made in the above composition and processwithout departing from the scope of the invention herein involved, it isintended that all matter contained in the above description shall beinterpreted as illustrative and not in a limiting sense.

What is claimed is:

1. A photographic processing composition comprising, in alkaline aqueoussolution, a plurality of agents including a first complexing agentcomposed of a cyclic imide selected from the class consisting ofcompounds within the general formula:

wherein Z represents (1) atoms of a series completing a cyclic imidenucleus, said nucleus consisting of from 5 to 6 atoms of which from 1 to3 are nitrogen and the remainder are carbon and (2) members branchingfrom said atoms of said series, said members being selected from theclass consisting of hydrogen atoms, amino radicals, aliphatic radicalscontaining from 1 to 4 carbon atoms, halogen atoms, keto oxygen atoms'and aromatic radicals, at most one of said members being one of saidhalogen atoms, keto oxygen atoms and aromatic radicals, a secondcomplexing agent other than a cyclic imide and composed of at least onenitrogenous base other than a hydroxylamine, said nitrogenous base beingselected from the class consisting of ammonia, organic amines, hydrazineand aliphatic hydrazines, and a developing agent composed of ahydroxylamine, said first complexing agent and said second complexingagent together being capable of reacting with silver halide to form awater-soluble complexing silver salt, said developing agent beingcapable of reducing silver halide to silver, and said second complexingagent performing a complexing function exclusively.

2. The photographic processing composition of claim 1 wherein thealkalinity of said solution ranges from a pH of 11 to a hydroxyl ionconcentration of 5 N.

3. A process of forming a photographic print, said process comprisingthe steps of reacting substantially exposed silver halide of aphotosensitive silver halide element with a silver halide developercomposed of a hydroxylamine, reacting substantially unreduced silverhalide of said photosensitive silver halide element, in alkaline aqueoussolution, with a first complexing agent and a second complexing agent,said first complexing agent being a cyclic imide selected from the classconsisting of compounds represented by the general formula:

wherein Z represents 1) atoms of a series completing a cyclic imidenucleus, said nucleus consisting of from 5 of which from 1 to 3 arenitrogen and the remainder are carbon and (2) members branching from ofsaid series, said members being selected from the class consisting ofhydrogen atoms, amino radicals, aliphatic radicals containing from 1 to4 carbon atoms, halogen atoms, keto oxygen atoms and aromatic radicals,at most one of said members being one of said halogen atoms, keto oxygenatoms and aromatic radicals, Said second complexing agent being composedof a nitrogenous base other than a hydroxylamine and other than a cyclicimide, and being selected from the class consisting of ammonia, organicamines, hydrazine and aliphatic hydrazines, said second complexing agentperforming a complexing function exclusively, transferring said complexby diffusion to an image-receptive material, and forming, at saidimage-receptive material, an image incorporating silver from said silvercomplex.

4. The photographic process of claim 3 wherein the alkalinity of saidsolution ranges from a pH of 11 to a hydroxyl ion concentration of 5 N.

References Cited in the file of this patent UNITED STATES PATENTS 122,543,181 Land Feb. 27, 1951 2,551,134 Jennings May 1, 1951 2,567,109Howard Sept. 4, 1951 2,590,775 Kendall et al Mar. 25, 1952 2,635,048Land Apr. 14, 1953 OTHER REFERENCES Kraft: Zeitschrift fiirWissenschaftliche Photographic, Photophysik und Photochemie, vol. 31,No. 12, May

10 1933, pages 329-364.

Mannessier-Mameli: Chemical Abstracts, 1936, vol. 30, page 2949.

Merck Index, published by Merck and Co., Inc., Rahway, N. J., 1952, 6thedition, pages 297 and 986.

Howe Dec. 19, 1950 15 Brune: Chemical Abstracts, 1952, vol. 46, page7448.

1. A PHOTOGRAPHIC PROCESSING COMPOSITION COMPRISING, IN ALKALINE AQUEOUSSOLUTION, A PLURALITY OF AGENTS INCLUDING A FIRST COMPLEXING AGENTCOMPOSED OF A CYCLIC IMIDE SELECTED FROM THE CLASS CONSISTING OFCOMPOUNDS WITHIN THE GENERAL FORMULA: